| asn | Provides support for Abstract Syntax Notation One |
| common_test | A portable framework for automatic testing |
| compiler | A byte code compiler for Erlang which produces highly compact code |
| crypto | Cryptographical support |
| debugger | A debugger for debugging and testing of Erlang programs |
| dialyzer | The DIALYZER, a DIscrepancy AnaLYZer for ERlang programs. |
| diameter | Diameter |
| edoc | A utility used to generate documentation out of tags in source files. |
| eldap | eldap - Erlang LDAP library |
| erl_docgen | A utility used to produce the OTP documentation. |
| erl_interface | Low level interface to C |
| et | Event Tracer (ET), uses the built-in trace mechanism in Erlang and provides tools for collection and graphical viewing of trace data. |
| eunit | Support for unit testing. |
| ftp | FTP client |
| hipe | High Performance Erlang |
| inets | A set of services such as a Web server and a ftp client etc. |
| jinterface | Low level interface to Java |
| kernel | Functionality necessary to run the Erlang System itself |
| megaco | Megaco/H.248 is a protocol for control of elements in a physically decomposed multimedia gateway, enabling separation of call control from media conversion. |
| mnesia | A heavy duty real-time distributed database |
| observer | Observer, tools for tracing and investigation of distributed systems |
| odbc | An interface to relational SQL-databases built on ODBC (Open Database Connectivity). |
| os_mon | A monitor which allows inspection of the underlying operating system |
| otp_mibs | SNMP management information base for Erlang/OTP nodes. |
| parsetools | A set of parsing and lexical analysis tools |
| public_key | API to public key infrastructure. |
| reltool | Reltool is a release management tool. It analyses a given Erlang/OTP installation and determines various dependencies between applications. The graphical frontend depicts the dependencies and enables interactive customization of a target system. The backend provides a batch interface for generation of customized target systems. |
| runtime_tools | Runtime tools, tools to include in a production system |
| sasl | The System Architecture Support Libraries is a set of tools for release upgrades and alarm handling etc. |
| snmp | Simple Network Management Protocol (SNMP) support including a MIB compiler and tools for creating SNMP agents |
| ssh | Secure Shell application with sftp and ssh support |
| ssl | ssl- Secure Socket Layer. |
| stdlib | The Erlang standard libraries |
| syntax_tools | A utility used to handle abstract Erlang syntax trees, reading source files differently, pretty-printing syntax trees. |
| tftp | TFTP application |
| tools | A set of programming tools including a coverage analyzer etc |
| wx | A Graphics System used to write platform independent user interfaces |
| xmerl | Provides support for XML 1.0 |